Economic indicators

Googling the future

Internet search data may be useful for forecasters

CLAIMS of clairvoyance, particularly when they come from economists, deserve a sceptical reception. Hal Varian, a professor of economics at the University of California, Berkeley who also happens to be Google's chief economist, has no such pretensions, but he does believe that data on internet searches can help predict certain kinds of economic statistics before they become available.

In a new paper written with Hyunyoung Choi, a colleague at Google, he argues that fluctuations in the frequency with which people search for certain words or phrases online can improve the accuracy of the econometric models used to predict, for example, retail-sales figures or house sales. Actual numbers for such things are usually available only with a lag. But Google's search data are updated every day, so they can in theory capture shifts in consumer behaviour before official numbers are released.

These data are available through a site called Google Trends, which allows anyone who cares to do so to download an index of the aggregate volume of searches for particular terms or categories. Mr Varian and Ms Choi show that the addition of these search trends to econometric models improves the accuracy of their estimates.

For example, using data on searches for trucks and SUVs to predict the monthly sales of motor vehicles reduces the average error by up to 18% compared with the predictions from a model that did not incorporate the search data. The volume of searches for Hong Kong carried out in countries like America, Britain, Australia and India also seems to predict eventual tourist arrivals to the territory from these countries rather well.

How widely could this idea be applied? For some things, like retail sales, the categories into which Google classifies its search-trend data correspond closely to what people may want to predict, such as the sales of a particular brand of car (see chart). For others, like sales of houses, things are less clear. It appears that searches for estate agents work better than those for home financing. But anything that makes the crystal ball less cloudy is welcome.